Op without wishing to give too much personal info away I have been involved in scenarios and dating inc OLD hook up sites etc where the men contacting me were younger, fitter, slimmer and better looking than me - not low self esteem speaking just an objective assessment
Before these particular experiences I had for years avoided responding to messages and approaches from such men, then I had a bit of an epiphany and basically went "Fuck it!" I finally acknowledged and accepted that confidence is the key.
I am 48, currently about a size 20, but this was only a few years ago and I wasn't much slimmer (16-18) with stretch marks, c section scar, other scars from surgeries, I have a birthmark on my face (which i was too self conscious about for decades), I have unfashionable natural colouring (very pale freckle skin couldn't tan if I tried! Red hair), I'm
Short so I don't carry the weight well.
I started taking my cue from what would now be described as body positive women I knew in real life, who dressed sexy and colourful if they wanted to, were very confident in approaching and flirting with men
I realised it was my own hang ups preventing me from enjoying myself.
I started buying and wearing more revealing and more colourful clothes and putting pics of the new me on OLD.
I hadn't lost loads of weight, I didn't photo shop I even stopped curating the pics to edit out the ones that showed my tummy apron or bingo wings etc but showed me having a good time and smiling confidently
I got way more interest and messages, I was sceptical at first still but I went on some of the dates and had some fun and I discussed this with one particular fwb I developed that arrangement with and he and others all said it's confidence that's attractive, it's things like knowing how you look but not letting the less attractive parts phase you and celebrating yourself as a whole person.
Now without wishing to brag I've dated some very gorgeous people since my mindset changed and had some of the best sex of my life!
He knows what you look like, he's presumably not an idiot who thinks you'll transform into some lithe barbie doll as soon as your coats off? AND I'm sure he has parts of his body he's not completely happy with too. Lots of men worry about receding hairlines, lack of muscle, flab, dodgy tatts they got as daft youngsters and can't afford to remedy, and of course their penises! Sooo many worry about that!
Focus on enjoying your time with him and getting to know each other. Everything else will come naturally if you're compatible (by which I mean personality wise)
I've honestly had "Shirley Valentine" moments where the person I was with in that moment has kissed and celebrated my stretch marks, my scars.
I'll admit women tend to be better tuned in to knowing what other women are likely to be insecure or worried about but then other women also need reassurance for their insecurities which can become a bit "mutual reassurance society" in bed at times 
As a bisexual woman (I hope this comes across ok) I would not be put off a woman because of extra weight or stretch marks or scars, they're all part of that person and beautiful for it.
I genuinely hope that helps